Method for changing the size of wax ring patterns

ABSTRACT

A method for accurately changing the inside diameter of wax patterns for finger rings. A portion of the band of the wax pattern on each side of the sprue piece is removed and a bar of the desired size is inserted in the ring. The ring and bar are affixed to mold and wax is injected through a bore hole in the mold and into the open portion of the band of the ring for completing the same. The mold has means for gripping the bar and comprises a cavity with a design therein.

0 United States Patent 1 3,56 1,52 1

[72] lnvemor George e 3,041,689 7/1962 Peras 164/35 Hiahah, 3,396,9348/1968 Ferris 164/35 [21 Appl. No. 803,009 3,402,754 9/1968 Christian164/35 22 Filed 27 9 9 3,402,755 9/1968 Christian 164/35 45 p d F b 9,1971 3,418,407 12/1968 Eilers 264/221X [7 ign Micro'ThermalApplications, Inc. Re26,785 2/1970 Kaplan 164/34 Hialeah F" PrimaryExaminer-Robert F. White a corporanon of Delaware AssistantExaminer-Allen M. Sokal Att0rney-Ryder, McAulay & Hefter [54] METHOD FORCHANGING THE SIZE OF WAX RING PATTERNS 4 Claims, 7 Drawing Figs. [52]U.S.Cl 164/45, ABSTRACT; A method f accurateuy changing the inside 1 4/2 /1 2640261264259 diameter of wax patterns for finger rings. A portionof the t of the wax attern on each ide of the p ue iece i [50] Field ofSearch 264/226, removed and a bar f the desired Size is inserted in thering 225,221,259,219, 152, 138; 164/45, 17, 34,3 The ring and bar areaffixed to mold and wax is injected through a bore hole in the mold andinto the open portion of [56] Reerences Cited the band of the ring forcompleting the same. The mold has UNITED STATES PATENTS means forgripping the bar and comprises a cavity with a 2,790,220 4/1957 Fox164/35 design therein.

METHOD FOR CHANGING THE SIZE OF WAX RING PATTERNS BACKGROUND The lostwax process involves making a wax pattern for every casting to beproduced. These patterns are made by the injection molding of wax intoprecision metal dies. The wax patterns, with sprues attached, areaffixed to a plate or base and the assembly is placed in a metal flaskwhich is then filled with a refractory investment mixture. After theinvestment material has hardened, it is inverted in an oven at anelevated temperature and the wax pattern is melted out of theinvestment. Molten metal is then poured into the investment to form thefinal product such as a ring. After the metal solidifies, the investmentis broken away and the casting is removed and finished by polishing.

The metal dies used in the above process are difficult and costly tomake. In making rings, one or two dies of a standard size are used forall wax patterns. The wax patterns are therefore made in standard sizes,such as size for men and size 7 for women. In order to make a differentsize ring, a wax pattern is first made in the standard size. The sprueportion of the ring is then cut out and the ring is placed on a atapered mandrel which is scored with the various ring size markings. Ahot iron is dipped into a reservoir of wax and the ring opening is thenwelded to close the band of the ring.

The disadvantages of this method are threefold. The welding obliteratesany decorative detail in the area of the weld. In addition, the weldedportion is tapered in accordance with the shape of the tapered mandrel.After the weld is completed, the sprue must be replaced carefully ontothe ring for proper formation of the investment.

The present method overcomes the above objections and disadvantages inthe prior art by the provision of a method described and shown in thefollowing specification and drawings.

THE INVENTION A wax pattern is formed by any conventional technique. Inthe improved method and means of this invention, the wax pattern is cuton each side of the sprue and a bar, such as a cylindrical bar. havingthe desired diameter is then placed within the ring. The portions of theband adjacent the cut portion are then positioned against a half moldwhich has the desired detail for the band portion of the ring. The moldalso has a bore hole or gateway which is then placed against a waxinjector. The wax is injected into the half mold and seals the band ofthe ring. At the same time, the desired detail on the band of the ringand an appropriately positioned sprue are formed on the ring. The halfmold includes means for gripping the cylindrical metal member andpressing it against the half mold.

The invention is set forth in greater detail in conjunction with theattached drawings in which:

FIG. 1 is a perspective view of a standard size wax pattern for a fingerring.

FIG. 2 is a perspective view of the pattern shown in FIG. 1 with thesprue and a portion of the band cut away.

FIG. 3 is a front elevation of the ring shown in FIG. 2 illustrating thereduction of the internal diameter.

FIG. 4 is a top view of the half mold for remaking the band portion ofthe wax pattern.

FIG. 5 is a sectional view of the mold of FIG. 4 through 5-5, with aring positioned thereon.

FIG. 6 is a sectional view of the mold of FIG. 4 through 6-6 and of aring thereon.

FIG. 7 is a perspective view of the pattern shown in FIG. I having areduced inside diameter.

- Referring to FIG. I, a wax ring pattern 11 of a standard size is shownwith an inside diameter D. An integral cylindrical sprue 12 extendsnormal to the lower or narrow side of the band and is normally used forthe handling thereof and to form a gateway for the latter pouring ofmetal into an investment.

Dual ridges I3 are shown which are representative of the designs whichmay appear on the band portion of the ring.

FIG. 2 shows the first step in the preparation of a ring of a changedsize. The sprue l2 and an adjacent portion I4 of the band of the patternhave been removed. This is accomplished by merely cutting through theband portion of the ring with a knife or other sharp or heatedinstrument.

FIG. 3 illustrates the reduced inside diameter d of the pattern lldesired. Alternatively, the inside diameter d may be slightly largerthan the original diameter D. The new inside diameter of the ring isdetermined bythe diameter of member IS. The term cylindrical as used formember is is intended to encompass the oblong shape which is used formany rings wherein the diameter d, as shown in FIG. 3. is not as greatas the diameter in a direction perpendicular thereto.

FIG. 4 is a top view of a half mold 16 for use in the present invention.A gateway l7 communicates with one side of the half mold and mold cavity18. The mold cavity includes grooves I9 representative of a design whichis desired for the band portion of the ring. The cavity 18 is. shaped toform a segment of the band portion. The half moldl includes holes 20 forthe purpose set forth in greater detail below.

A cross section of the half mold I6 through lines 5-5 is shown in FIG.5. A ring lll having a cylinder 15 therein, corresponding to thearrangement shown in FIG. 3, is secured to the half mold by means of abar 21 through the center of the cylinder. The bar 21 is attached to thehalf mold by securing means 22 in holes 20. This arrangement is formedby positioning a cylinder 15 within the ring Ill and compressing thering tightly around the cylinder. The ring is then placed into thecavity 18 of the half mold 16 while maintaining a compressive force onthe ring. Simultaneously, the securing means 22 are tightened tomaintain a tight fit between the half mold, the ring, and the cylinder.One of means 22 may be shorter than the other to assist in holding thewax pattern securely against the half mold and in the cavity.

A cross-sectional view through lines 6-6 of FIG. 4 is shown in FIG. 6 toillustrate the manner in which the opening in the band of the ring isaligned with the gateway 17 in the half mold 16.

The change in ring size is completed by placing the enlarged portion 23of the gateway I7 against the nozzle of a molten wax injector. Theinjector is of conventional construction and is not shown herein. Itcomprises a reservoir of wax which is maintained in a molten condition.Upon pressing the gateway opening 23 against the injector nozzle, an aircylinder is actuated to force the liquid wax into the half mold. Theflowing wax closes the opening in the band and reforms the sprue anddesired design characteristics.

The completed wax pattern is shown in FIG. 7. The above process anddevice provides a new band portion 24 within dotted lines 25. The design26 corresponds with the grooved portions of the half mold l9 and thesprue 27 is properly positioned on the band. Note that the sprue 27 andreformed por' tion 24 would normally be, opposite the stone portion 28of the ring. The removal and reforming of this. portion preserves thesymmetry of the ring and is usually at the narrowest portion of thering.

This invention has been described in terms of specific embodiments setforth in detail. Alternative embodiments will be apparent to thoseskilled in the art in view of this disclosure, and accordingly suchmodifications are to be contemplated within the spirit of the inventionas disclosed and claimed herein.

lclaim:

I. The method of changing the size of a wax pattern for a ring having afirst predetermined diameter which comprises removing a portion of theband of said ring, inserting a bar having a second predetermineddiameter into the band of said ring, compressing said ring around saidbar to maintain contact between said band and said bar, positioning saidband including the space leftby said removed portion in a mold having acavity which corresponds to the desired shape of said 3. The process ofclaim 1 wherein said cavity has a shape which produces a desired designon said band upon injecting of said wax.

4. The process of claim 2 wherein said positioning of said band and saidbar into said mold comprises attaching said bar to said mold.

1. The method of changing the size of a wax pattern for a ring having a first predetermined diameter which comprises removing a portion of the band of said ring, inserting a bar having a second predetermined diameter into the band of said ring, compressing said ring around said bar to maintain contact between said band and said bar, positioning said band including the space left by said removed portion in a mold having a cavity which corresponds to the desired shape of said band, injecting wax into said mold to reform said band solidifying said wax, and removing said pattern from said bar and said mold.
 2. The method of claim 1 wherein said wax pattern includes a sprue on said band, which comprises removing said sprue and closely adjacent areas of said band, and positioning said band and bar into said mold which contains a gateway communicating with said cavity.
 3. The process of claim 1 wherein said cavity has a shape which produces a desired design on said band upon injecting of said wax.
 4. The process of claim 2 wherein said positioning of said band and said bar into said mold comprises attaching said bar to said mold. 